Realistic Gingerbread Material
Here is what I did





For the displacement, I mixed different Noise Textures with different settings to them with a bunch of Mix RGB nodes. At the end, I mixed the Noise textures with a Musgrave texture too add some lumpiness to the displacement.

You can play around with the noise settings to achieve the look you want.

For the color, I attached the noise textures to a color ramp, black being a darker brown, and white being a lighter brown, and plugged that into the base color of the principled BSDF shader.

I didn't change any of the BSDF shader settings, but I realized it might help if you increased the roughness.

I hope I helped out.